Boring holes in rock



Sept. 16, 1969 H, LAUTSCH ET AL BORING HOLES IN ROCK 8 Sheets-Sheet 1Filed July 14, 1967 3 I; I l i I l I I I l I I l I I. I m9 m9 8? g H m9N LII lvl 87 5 H 9 N 6E IN VENI'ORS Hans-Z u div/9 .14 (02%? Herman/7LAUTSCl-l Pele/- HERMA NNS Klaus HRMANN$ Sept. 16, 1969 H, L u'rscH ETALBORING HOLES IN ROCK 8 Sheets-Sheet 2 Filed July 14, 1967 NQE INVENTOSept. 16, 1969 Filed July 14, 1967 BORING HOLES IN ROCK H. LAUTSCH ETAL8 Sheets-Sheet 3 Sept. 16, 1969 LAUTSCH ETAL BORING HOLES IN ROCK 8Sheets-Sheet 4 Filed July 14, 1967 //V VZNTORS Hans iuo'w/g 1A 608Hermann A (/78 CH Pefer l/'RMA NNS K lavas HHPMAA/NS v GI Sept. 16, 1969u'rsc ET AL BORING HOLES IN ROCK 8 Sheets-Sheet 5 Filed July 14, 1967INVENTORS fiansi udlwjg 1A [08 Hermann LAl/TSCH Pefer HERMAN/V5 KlausHERMAN/v5 Sept. 16, 1969 u'rscH ET AL 3,467,210 BORING HOLES in ROCKFiled July 14, 1967 8 Sheets-Sheet 6 507 T 507 505 w5o 5 572 INVENTORS:

Hans-ladm'g M605 Hermann LAUTSCH Pe/er HERMANNS Klaus HERMAN/Vs Sept.16, 1969 u sc ET AL 3,467,210

BORING HOLES IN ROCK Filed July 14, 1967 8 Sheets-Sheet 7 //V WEN/0R5Hans-Ludwig ./A (03 filer/77mm LAUTSC/y Peter I/ERMA/VNS KlausI-IERMANNS Sept. 16, 1969 u1's ETAL BORING HOLES IN ROCK 8 Sheets-Sheet8 Filed July 14, 1967 INVENTORS United States Patent Int. Cl. E211)9/22; lZZlc 23/00, 13/04 US. Cl. 175386 Claims ABSTRACT OF THEDISCLOSURE The specification describes various forms of boring headshaving cutting tools arranged to cut along a helical or helical-spiralpath and thus produce a forward thrust. When such tools are placed onthe periphery of the head they produce a correcting thrust when the headstrays from a softer stratum into a harder one.

The present invention relates to boring apparatus for producing circularholes in rock and more particularly but not exclusively to such boringapparatus in which a rotation of tools on the apparatus produces athrust tending to force the apparatus forward along the direction of thehole being bored.

Generally the invention is intended to be applicable to apparatus forboring holes in rock of many different sizes extending from holes of theorder of one foot the diameter to those of the largest size used in coalmining practice.

An object intended to be obtained with certain forms of the invention isto place the tools at the periphery of the boring apparatus in such amanner that they produce a forward thrust along the axis of the holeowing to their engagement with the adjacent rock. An advantage of such ameasure is that if the boring apparatus is used in a stratum which issofter than the underlying and overlying stratum as is commonly the casewith coal, and if the boring apparatus runs against one of the harderstrata, the tool at the periphery of the apparatus will, owing to thegreater hardness, produce a relatively greater thrust and thus tend toturn the apparatus so that it runs back into the softer strata in whichit is intended to operate. This is an advantage over constructions inwhich a. heavy axial feed pressure is required since if such devicesengage a harder stratum below or above the stratum in which they areintended to be working they tend to be tilted by a harder stratumtowards it.

The present invention consists in a boring apparatus for producingcircular holes in rock comprising a frame adapted to be turned about anaxis coinciding with the axis of the hole to be produced and to be fedalong the axis of the hole, rock cutting means arranged on the frame andto rotate with the frame about the axis of the hole so that any givenpoint on the cutting means follows a helical path corresponding with therotation of the frame and its feed along the axis, the principal cuttingaction of the cutting means corresponding to a torque about the frameaxis, the cutting means having the further feature that it extends alongat least one line which when projected radially on to an imaginarycylinder around the frame axis it produces a helix.

Preferably the apparatus is so designed that when used in the stratumfor which it is intended, for instance coal, only torque is required todrive it and the axial thrust is produced by the action of the cuttingtools.

In accordance with a preferred feature of the inven- 3,467,210 PatentedSept. 16, 1969 tion the cutting means are arranged on at least two suchlines.

Preferably each line along which the cutting means extends is itself ahelix.

The frame can have a substantially cylindrical surface, coaxial with theframe axis, on which the cutting means is mounted, this cutting meansbeing arranged to cut the hole to its final dimension. The cutting meanscan comprise separate cutting tools of which the most forward isarranged to cut a helical groove which is progressively widened in arearward direction by the following cutting tools of the cutting means.

The projection of the line on which the cutting means is arranged on toa radial plane can be a spiral.

The frame can comprise two sections arranged to rotate in oppositedirections about the hole axis, and two such cutting means, one cuttingmeans being arranged on each such frame section. The outer-most of thetwo frame sections can be arranged to rotate at a slower speed than theinner one so that the net torque exerted on the frame is zero.

The angle of the helix of the line on which the cutting tools arearranged can have such a large value that cutting tools in the form ofcutting rollers can be used.

Some embodiments of the invention are now described with reference tothe attached drawings.

FIG. 1 is a diagram of a conventional boring apparatus.

FIG. 2 is a developed view of a boring apparatus in accordance with theinvention with boring tools arranged to engage a coal seam in asubstantially radial-tangential direction.

FIG. 3 is a diagram of an embodiment to the invention in a positioncorresponding to that of FIG. 1.

FIG. 4 is a diagram showing the action of tools of the boring apparatusshown in FIG. 2.

FIG. 5 shows, diagrammatically, a further embodiment to the invention inperspective view from the front.

FIG. 6 is a perspective view of a further embodiment Of the invention.

FIG. 7 is a view corresponding to FIG. 6 showing a modified embodimentto the invention.

FIG. 8 is a side view of the cutting tools of the boring apparatus inaccordance with FIG. 7.

FIG. 9 is a diagram showing a helicoidal surface.

FIGS. 10 and 11 show a further embodiment of the invention in which theframe is generally wheel-shaped.

The boring apparatus of conventional construction shown in FIG. 1 isprovided with axially acting cutting tools, that is to say tools whichprincipally require an axial thrust, rather than a torque tending torotate them about the axis of the hole, on its front face 100. Theboring apparatus is shown in a coal seam 101 softer than the strataabove and below it. The boring apparatus 102 is attached to the end of adriving rod 103 which is driven in a conventional manner by a boring ordrilling machine. Reference numerals 104 and 105 denote the boundariesof the overlying and underlying strata respectively.

If the feed or thrust force 109 acting on the boring apparatus isequally distributed by the front face of the apparatus on to the coalthere will be no tilting movement acting on the apparatus and it willremain in a central position.

If however the boring apparatus for some reason or other follows thepath 106 shown in broken lines and runs into the boundary 105 of thelower harder stratum there will be more resistance to the bottom of thefront face of the boring machine than to the rest of it as indicated byarrow 107. In consequence the counter pressure on the front face willtend to act along the arrow 108 displaced from line 109 and the boringapparatus will tend to increase its angle of dip in a saggital plane andleave the softer coal seam.

In accordance with one form of our invention we therefore provide on thefront of a boring apparatus 102a picks or similar working tools arrangedon the front of the cylindrical outer face of the apparatus which isarranged to rotate. These picks out the coal owing to the rotation andare arranged on a helical line about the axis of rotation. It can beseen from FIG. 2 that an imaginary line, not shown in the figure,running through the centers of the picks makes a greater relix angleabout the axis of the boring apparatus than the helix angles of thehelical paths of the individual picks. As a result of this the cuttingof the harder underlying stratum of the rock in general in which theapparatus is working, in the zone A is as shown in FIG. 4. In this casethe pick 1 furthest to the front first cuts a groove 1 as shown in FIG.4 and the groove is successively widened out as indicated by referencenumerals 2 to 16 in the figure. As a result of this backward cutting ofthe groove to widen it out along the extent L there is a thrust alongthe axis of the hole towards the front. In the particular case shown thegreater hardness of the underlying stratum with the boundary surface105a means that there will be a greater forward thrust at the bottom ofthe boring apparatus than at the top, these unequal thrusts beingrepresented by reference numerals 107a and 10717. This may also beconventionally expressed by the arrow 108a indicating reaction beingplaced higher than the forward thrust 109a due to the rod 103a as shownin the figure. As a result the boring apparatus is tipped in a saggitalplane and runs back into the coal, leaving the softer stratum. If thetop boundary 106a of the hole being produced should run into theboundary between the upper harder stratum 104a and the coal seam 101athe result will be that the thrust 1071? will become greater than thethrust 107a, and the boring apparatus will be tipped back into the coalseam.

In the embodiment of the invention as shown in FIG. 5 the boringapparatus 202 is mounted on a driving or boring rod 203. Boring picksshown diagrammatically and similar to those used in the precedingembodiment of the invention, 301-313 are mounted on the cylindricalouter face of the boring apparatus and are arranged to cut the coal toits fina1 dimension.

On the front face 200 of the boring apparatus we provide suitablymounted picks 314-329 arranged along two lines on parts 210 and 211 insuch a manner that the cutting edges of the picks extend along lineswhose radial projection on to an imaginary cylinder about the axis ofthe boring apparatus represents a double start helix while theirprojections on to a radial plane represent a spiral. The picks, whichcan be of a construction well known in the art and are therefore notshown in detail, have a rake angle.

The cutting tips of the picks can also be set to lie on two helicoidalfaces. In order to facilitate the understanding of the invention ahelicoidal face is shown in FIG. 9. In this case the generatrix is astraight line 401 which rotates about the axis 402, the angle betweenthe two being a right angle so that a right helicoidal surface isproduced. A helicoidal face produced by rotation through 180 is shown inperspective and denoted by reference numeral 407. The term helicoid orheilcoidal surface extends to cover cases in which the generatrix iscurved or is a straight line not at a right angle to the axis ofrotation.

FIG. 6 shows the front face 504 of a further embodiment of the inventionwhich rotates about an axis 503 corresponding to the axis of rotation212 of the previous embodiment to the invention. The boring apparatus ismounted centrally on a boring rod. The frame part 504 has two carriers505 on which there are mounted curved segments 506 carrying teeth orpicks 507 arranged so .4 that their cutting edges lie in a helicoidalsurface, for instance in accordance with 407 indicated in FIG. 9.

The arrangement of the picks 507 on the carriers 506 is showndiagrammatically in FIG. 8. From this figure it can be seen that thebodies of the picks run towards the axis 503 of the apparatus and alsoare inclined some what to the rear.

In operation the rotation and forward feed of the boring apparatuscauses the picks to generate a helicoidal cutting surface on the coal.The rate of feed can be arranged to be so great that the cutting means,that is to say the picks 507 exert a forward thrust similar to theaction of a tap cutting a screw thread.

The further embodiment of the invention shown in FIG. 7 has a frame madein two sections arranged to rotate in opposite directions, 501 and 520,about the axis of the bore. The inner frame section has picks or othercutting tools mounted on it as shown in FIG. 6 while the outer sectionhas two carriers 511 with flanges such as 512 on which picks are alsocarried. However the picks in the latter case and the flanges 512correspond with helicoidal surfaces having the opposite hand to those ofthe helical surfaces with which the picks on parts 506 are mounted. Theflanges 512 run from the outer edge 510a of the inner frame section andextend over the edge 510b of the outer segment.

In operation the speed of rotation of the outer section 510 is less thanthat of the inner one so that, by a suitable choice of the speed ratiothere is a zero or minimum net rotational force on the boring apparatus.In order to allow for the different speeds of rotation the helicalangles of the lines in which the cutting means, that is to say picks,are arranged on the inner section on the one hand and the outer sectionon the other hand can be different.

Instead of using fixed picks such as 314-329 in FIG. 5 or 507 FIG. 6 itis possible to use a cutting chain of the type well known in the art. Ifuse is made of cutting rollers then the angle between the generatrix ofthe helical surface to which the cutting edges correspond and to theaxis of rotation on the rear side of the generatrix can be such that thecutter rollers can be placed one behind the other.

In the embodiment of the invention shown in FIGS. 10 and 11 the framecomprises an outer hoop portion 601 coaxial with the axis of rotation, acentral hub portion connoted by general reference numeral 602 and spokes603 connecting the two together. On the hub 602 to one side of thespokes we provide a connecting means in the form of a conically threadedstem 604 while on the other side there is a drill 605 for boring a pilothole in advance of the tools to be described. The apparatus furthercomprises spirally shaped tool support means 606 which extend frompoints of attachment to the hub 602 along two approximately spiral padsto attachment points on the hoop portion 601. The cutting means is inthe form of separate rock cutting tools or picks 607 of the type used incutting chains. Each cutting tool has a tungsten carbide cutting insert.The planes of the cutting edges of the tools converge generally towardsthe hub 602. The bodies of the tools slope in a direction towards therear and towards the hub so as to keep them clear of the rock face to becut. The boring apparatus further comprises cutting plates 608 withsharp edges conforming substantially to lines drawn through the tips ofthe other cutting tools 606. These lines can project it radially on toan imaginary cylinder coaxial with the axis of rotation produce heliceswhile in an axial projection on to a radial plane they produce spirals.

The boring apparatus just described, which can be made with a diameterof 30 cm., can conveniently be used for boring holes upwards in coal.

What we claim is:

1. A boring head for cutting circular holes in rock comprising acircular body adapted to be rotated about an axis coinciding with theaxis of the hole to be cut, said body having a relatively flat face, apair of spirally shaped tool supporting segments projecting from saidface, said segments extending from points near the body axis andspiralling in opposite directions to terminal points near the peripheryof the body, the forward surfaces of said se ments being helicoidal withthe highest points thereof disposed in the region of the body axis andthe lowest points thereof disposed in the region of the body periphery,and cutting instrumentalities on said segments disposed in helicoidalfashion.

2. A boring head as claimed in claim 1 comprising an additional bodycoaxial with said first body and similarly structured and rotatableindependently thereof, whereby one body may rotate in one direction andthe other in the opposite direction.

3. A boring head as claimed in claim 1, in which said body comprises anouter hoop portion coaxial with the axis of rotation, a central hubportion, spokes connecting said hub portion with said hoop portion,connecting means attached to said hub portion on one side of saidspokes, said segments extending from points of attachment to said hubportion on the other side of said spokes along approximately spiralpaths to attachment points on said hoop portion, said cuttinginstrumentalities being in the form of separate rock cutting toolsarranged on said segments, the planes of the cutting edges of said toolsconverging generally towards said hub portion, and the bodies of saidtools sloping in the direction towards the rear and towards said hubportion, thereby to maintain them clear of the rock face to be cut.

References Cited UNITED STATES PATENTS 883,137 3/1908 Karns --385 X2,201,219 5/1940 Bell 175391 X 2,711,888 6/1955 Robbins 29988 X2,775,439 12/1956 McCarthy 175-391 X 2,798,707 7/1957 Kandle 29987 X2,864,601 12/1958 McCarthy et a1. 29987 3,085,795 4/1963 Snipe 299873,174,801 3/1965 Owen 175-391 X FOREIGN PATENTS 585,709 2/ 1947 GreatBritain.

NILE C. BYERS, 1a., Primary Examiner US. Cl. X.R. 175-394

